The history of artificial limbs goes back to very remote times. In fact, there is some evidence that the Romans and the Greeks may have improvised some sort of substitute for limbs lost as a result of battles and the vicissitudes of life. Herodotus tells us of a prisoner who amputated his own foot in order to free himself from the shackle, after which he escaped and returned to his friends, who made a wooden foot.
The treasure trove that turned up at Capua in 1885 in a tufa tomb is probably the most valuable and indisputable evidence that artificial legs were made in early times. The relic is now on exhibition in the Museum of the Royal College of Surgeons, London. The official catalogue describes it thus: “Roman artificial leg; the artificial limb accurately represents the form of the leg. It is made with pieces of thin bronze, fastened by bronze nails to a wooden core. Two iron bars, having holes at their free ends, are attached to the upper extremity of the bronze. A quadrilateral piece of iron, found near the position of the foot, is thought to have given strength to it. There was no trace of the foot, and the wooden core had nearly crumbled away.”
From those early times to about the beginning of the 20th century, little or no advance was made in the art; and, as no evidence exists to prove to the contrary, it is quite reasonable to suppose that for many centuries the manufacture of artificial limbs was one of the lost arts.
In the early part of the 20th century, the Duke of Anglesea, being in need of an artificial leg, and possessing an inventive faculty, suggested to an English instrument maker what proved to be a very answerable substitute, a decided improvement on the primitive peg of the doughty Peter. The leg received but little improvement until the venturesome Selpho introduced it into this country with some admirable modifications of his own; here it met with American enterprise and began to thrive.
Typically, artificial limbs are held in place by a series of straps or some type of suspension system. Some are suspended with a silicone sleeve that has a pin that locks in place.
The earliest use of a vacuum to attach an artificial leg was with above the knee amputees using what is known as a suction socket. The “suction socket” uses the same principle as a suction cup where the maximum strength of the force holding the objects together is a function of the atmospheric pressure at the altitude of use. In artificial leg usage the suction or vacuum is reduced by the vapor pressure of the sweat at the internal temperature of the socket. Use of suction sockets on below knee amputees was not initially practical. The next advance in using vacuum was the introduction of the Harmony system which uses a mechanical pump operated by the energy of walking Each step operates a pump.
A vacuum system improves the fit and comfort between the device and the residual limb. A vacuum pump forces out air through a one-way valve, creating negative pressure with every step the patient takes. A tiny tube connects the pump to a weight-bearing socket which is enveloped in a urethane liner or sleeve. By improving suspension, the prosthesis offers better control and less pressure on the limb and liner. The pump is powered by the wearer's body weight. Taking a step compresses the device, which creates the vacuum between the liner and the socket.
Through the years, many socket structures have been developed for use with vacuum and non-vacuum systems alike. Many of these structures are represented in the patent literature. For example, U.S. Pat. No. 2,634,424 to O'Gorman discloses a double-walled socket of resiliently flexible material.
U.S. Pat. No. 5,007,937 to Fishman deals with a structure for enhanced retention of artificial limbs and method of fabrication in which an air impermeable sealing band of rubberized material is introduced between the patient's stump and the interior of a stump-receiving socket of an artificial limb, in one of two ways, depending on whether or not the patient wears a stump sock. If the patient wears a stump sock, the band of sealant material is impregnated into the stump sock. If the patient does not wear a stump sock, an impregnated sock is incorporated into the interior structure of the socket of the patient's prosthesis. The impregnated sock itself is fabricated by placing a conventional stump sock on a somewhat oversized form. An appropriate annular region on the sock is then masked off by means of tightly fitting plastic bags, and one of the plastic bags provides an enclosing outer sheath which encompasses the annular region and extends upwardly above the form. A rubberized material in liquid form is introduced through the top of the outer sheath and a vacuum is introduced below to draw the material into the annular region of the sock, so as top impregnate the same. The rubberized material penetrates the sock, is worked into an axially contoured shaped, and is then permitted to set. A stump-receiving socket for an artificial limb with an integral annular seal is fabricated by placing a stump sock with the seal on a cast of a patient's leg and then laminating the socket over the sock using conventional procedures for manufacturing stump-receiving sockets.
U.S. Pat. No. 5,108,456 to Coonan shows a prosthetic appliance for residual limb is disclosed comprising a prosthesis member having a cavity defined by side walls formed of a rigid molded material. A separate removable molded socket member formed of a flexible material is nested within cavity of the prosthesis member and is adapted to receive the residual limb. Several separate, independently inflatable bladders preferably attached to the exterior of the socket member, when inflated, act against the rigid side walls of the prosthesis member to resiliently force discrete portions of the socket member side walls inwardly to grip the residual limb. An inflation control means is provided in the form of at least one manually operable air pump and one or more manually operable air valves, one for each of said bladders, for selectively inflating the associated bladder separately and independently from the other bladders, so that the gripping pressure of the residual limb at each discrete portion of the socket member may be adjusted separately and independently by both the air pump and the air valves.
U.S. Pat. No. 5,156,629 to Shane is directed to a removable and adjustable prosthetic insert disposed between the stump of a limb and the socket of a prosthesis is comprised of a high strength, pliable polymeric material within which are formed a plurality of spaced air pockets, or voids, which are coupled together by a series of connecting channels, or passages. Using an air valve extending through the polymeric material and coupled to the closed air pocket/channel system, the air pockets may be inflated to fill the stump/socket inter-space and provide a tight-fitting, air cushioned prosthetic socket attachment. The air inflatable prosthetic insert can accommodate changes in the condition of the stump and applies a uniform prosthetic attaching force thereto. Other embodiments also employ an inflatable air cushion and make use of spaced, solid spheres disposed between air passages arranged in a grid-like array; and pinched tubing with interconnecting air passages to form a series of inflatable nodules. An air cushion isolates the limb stump from the hard, rigid prosthesis socket for user comfort and provides a custom fit for improved control and maneuverability of the prosthetic device.
U.S. Pat. No. 5,139,523 to Paton discusses an apparatus for mounting a socket above the knee of an amputee, wherein the socket is arranged for mounting a prosthesis to a lower terminal end thereof. The sleeve includes an internal cage formed of rigid rods, including hook members imbedded within a semi-spherical sleeve support, with the cage encased in a polymeric covering. A vent is provided through the sleeve support for venting interiorly of the socket. The socket may further include pneumatic chambers for enhanced comfort in support of the socket.
U.S. Pat. No. 5,888,231 to Sandvig describes a method of preparing a breathable, custom-molded liner for an artificial limb socket includes the steps of providing a liner comprising an open-celled foam material impregnated with a curable resin, activating the curable resin, and deforming the foam material by positioning a residual limb on one of opposing surfaces of the liner, and positioning the artificial limb socket on a second opposing surface of the liner until curing is substantially complete to create and retain an impression of the residual limb in the foam material. A liner blank useful for preparing an artificial limb socket, comprising a foam material impregnated with a curable resin and sewn into the shape of a sock for an artificial limb, is also described.
U.S. Pat. No. 6,585,774 to Dean involves a dynamic variable geometry prosthetic fitting system with fluid-filled bladders and automatically regulating their volumes to provide a continuously secure fit. This system can vary volume continuously to accommodate natural variation in an amputee's residuum. It makes reliable suction retention of a prosthesis easier for the prosthetist to achieve while reducing the potential for tissue lesions. By maintaining a continuous, secure fit, the amputee's sense of confidence and willingness to use the prosthesis increases.
U.S. Pat. No. 6,926,742 to Caspers is directed to a hypobarically-controlled artificial limb for amputees includes a single socket with a volume and shape to receive a substantial portion of the residual limb. A liner with a volume less than the residual limb is donned over the residual limb, with the liner tensioned into a total contact relationship with the residual limb. A sealed cavity is formed between the socket and the liner. A vacuum source is connected to the socket cavity thereby drawing the residual limb and liner into firm and total contact with the socket. To compensate for some air leakage past the seal, there is a mechanism to maintain the vacuum in the cavity. A plate/socket attachment connects the vacuum source to the cavity.
Among the disadvantages of known systems are size, weight, and difficulty of use. There are many amputees that cannot use known systems because of size (particularly smaller adults and children), age of the patient, and length of the stump. For many patients, the time-consuming steps and cumbersome strap systems involved in using known prostheses cause the patients to eschew prostheses entirely. Further, known sockets are subject to unhygienic conditions, as they collect perspiration from the residual limb, and bacteria and other contaminants from the ambient air surrounding the prosthesis.
It can thus be seen from the foregoing that the need exists for a prosthetic socket that ameliorates the drawbacks of known devices, while remaining easy-to-use, lightweight, and hygienic.
These together with other objects of the invention, along with the various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated embodiments of the invention.